Daylight saving time starts this weekend. Why do we 'spring forward'? How much sleep will we lose?

It’s time to spring forward. Beginning in the early morning hours this Sunday, the vast majority of the United States will enter daylight saving time.

Most states will set their clocks one hour ahead, or their digital devices will automatically change. The end result? We’ll lose an hour of sleep, and, in the long term, sunset and sunrise will be pushed an hour later, until the clocks fall back an hour in November.

While many people celebrate having more daylight at the end of the day, daylight saving time isn’t without controversy. Some lawmakers want to end the practice of changing our clocks entirely. So why do we have daylight saving time, and what could happen with it down the line? Here’s what to know.

When does daylight saving time start this year? When does it end? 

In the United States, daylight saving time starts at 2 a.m. local time on Sunday, March 8. On that day, clocks are set forward one hour in the early morning. It ends on Sunday, Nov. 1, when clocks are set back one hour.

Who participates in daylight saving time in the U.S.? Do other countries observe it too?

Observing daylight saving time is up to individual U.S. states — and not all of them do. Hawaii and most of Arizona (with the exception of the Navajo Nation) do not observe daylight saving time, nor do the U.S. territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico and the Virgin Islands.

And while daylight saving time is observed worldwide, not every country participates. In North America, much of Canada and parts of Mexico near the U.S. border participate. In fact, British Columbia’s Premier David Eby announced Monday that the province is switching to permanent daylight time. B.C.’s new time zone will be called “Pacific Time.”

Most of Europe practices daylight saving time as well, with the exception of countries like Iceland, Russia and Belarus.

While most of Africa and Asia do not participate, Israel, Lebanon, Cyprus and Egypt (a country that initially abolished the practice but has since reintroduced it) do. In South America, only Chile and Paraguay currently observe daylight saving time, and in Central America, no countries do.

Even in countries that observe daylight saving time, start and end dates vary, so it’s important to check how locals operate.

Why did daylight saving time start in the first place? 

Daylight saving time was created in 1918. The intention was to allow extra sunlight during the day to save on fuel costs, which was significant during World War I. It was reinstated during World War II and the early 1970s energy crisis.

Daylight saving time did not become federal law until 1966, with the passage of the Uniform Time Act, which created a standard national schedule for states that choose to participate.

Why are some people hoping to end daylight saving time? 

Many people are unhappy with daylight saving time because of the interruption it causes to sleep, which can have serious health consequences. Research suggests that the practice can lead to increased strokes, heart attacks and sleep deprivation (particularly for teens who attend school).

What efforts are being made to prevent clocks from being changed twice a year?

There have been recent efforts at the state and federal levels to sunset the twice-a-year ritual of changing the clocks.

State-level bills calling for permanent standard time and permanent daylight saving time are nearly evenly split.

At the federal level, the House of Representatives and Senate have their versions of the Sunshine Protection Act, which seek to make daylight saving time permanent nationwide. It was reintroduced in January 2025 in the 119th Congress but remains stalled in congressional committees.

In February, the Daylight Act of 2026 was introduced by Rep. Greg Steube, a Republican from Florida. Instead of keeping standard time year-round or daylight saving time year-round, the bill proposes a permanent 30-minute forward shift from standard time, or a “half-daylight saving time.” The bill currently remains in committee.